Understanding the Usage of Potassium Sparing Diuretics

• Potassium-sparing diuretics, also known as aldosterone inhibiting diuretics, have weaker diuretic and antihypertensive effects than other diuretics. 
• Mostly, they are combined with other diuretics to potentiate their action or counteract potassium wasting. 
• The most common and serious adverse drug reaction of these diuretics is hyperkalemia, especially if combined with a potassium supplement or taken with a potassium-rich diet. 

Potassium-sparing diuretics, also known as aldosterone inhibiting diuretics, have weaker diuretic and antihypertensive effects than other diuretics. But they have the advantage of conserving potassium, so hypokalemia does not occur.  

Mostly, they are combined with other diuretics to potentiate their action or counteract potassium wasting.  

With potassium-sparing diuretics, you have to monitor serum potassium because they possess the risk of hyperkalemia. Therefore these drugs should be used cautiously in moderate renal dysfunction and avoided in patients with severe renal dysfunction.  

The potassium-sparing diuretics include:

• Spironolactone  
• Eplerenone  
• Triamterene  
• Amiloride
  

They act on the collecting ducts and distal tubules of the kidneys. That results in the urinary excretion of sodium, water, bicarbonate, and calcium. Moreover, they also decrease the excretion of potassium and hydrogen ions, leading to reduced blood pressure and increased serum potassium levels. 

Spironolactone is structurally similar to aldosterone, which promotes sodium and water retention and potassium loss.

Being its antagonist, spironolactone counteracts these effects by competing with aldosterone for receptor sites. Hence, sodium, chloride, and water are excreted, and potassium is retained. 

Indications

These diuretics are used in: 

• Edema 
• Diuretic-induced hypokalemia in patients with heart failure because it spares potassium. Therefore it helps in replenishing potassium stores and is used to prevent hypokalemia.  
• Cirrhosis 
• Nephrotic syndrome  
• Heart failure 
• Hypertension 
• Hyperaldosteronism
  

Spironolactone is also used in hirsutism and hirsutism associated with the polycystic ovarian syndrome.  

Drug Interactions

• Potassium-sparing diuretics, when given with potassium supplements or ACE inhibitors such as captopril, enalapril, and others can result in hyperkalemia.  
• Spironolactone and digoxin, when used concurrently, can increase the risk of digoxin toxicity, leading to fatal arrhythmias. Therefore dose adjustment with their concomitant therapy is necessary.  
• Lithium, when combined with potassium-sparing diuretics, can result in lithium toxicity.  
• NSAIDs can decrease the action of potassium-sparing diuretics when given together.  

Adverse Reactions

The most common and serious adverse drug reaction is hyperkalemia, especially if combined with a potassium supplement or taken with a potassium-rich diet.  

Spironolactone can cause gynecomastia in males and menstrual cycle irregularities in females.  

Potassium Sparing Diuretics and the Nursing Process

With potassium-sparing diuretics, you should follow these nursing processes:

Assessment

• Before the therapy begins, check the patient’s baseline values. These include complete blood count (CBC)- including a white blood cell [WBC] count, liver function tests, and levels of serum electrolytes, carbon dioxide, magnesium, BUN, and creatinine. Make sure to review them periodically and watch them for significant changes. 
• As soon as the therapy begins, check the patient’s pulse rate and blood pressure, especially during rapid diuresis, to rule out hypovolemia. 
• Check the patient for evidence of excessive diuresis. Its symptoms are hypotension, tachycardia, poor skin turgor, excessive thirst, and dry and cracked mucous membranes. Consult with a physician soon if the patient has any of these signs.  
• Assess the patient for signs and symptoms of hyperkalemia, 
• such as confusion, hyperexcitability, muscle weakness, flaccid paralysis, arrhythmias, abdominal distention, and diarrhea. Along with them, check their serum potassium levels frequently.  
• Check the patient for edema and ascites. If the patient is mobile, check their legs, and if they are bedridden, check their sacral area.  
• Weight the patient every morning soon after he voids before breakfast. Ensure they are wearing the same clothing every day. Weight monitoring can help you know the patient’s response to diuretic therapy. 
• Carefully record the patient’s intake and output every 24 hours. 

Monitoring

You should monitor the patient for: 

• Hypovolemia due to excessive diuresis 

• Injury due to electrolyte imbalance 

Nursing Implementation

• To prevent nocturia that will hinder a patient’s sleep, administer diuretics early in the morning or early afternoon.  
• Make sure the bathroom is accessible to the patient because they will have an urgency to urinate. You can also keep a urinal or a bedpan accessible to them to prevent falls and injuries.  
• When potassium-sparing diuretics are administered to a patient with hepatic dysfunction, reduce the dose. And for patients with renal impairment, oliguria, and decreased diuresis, increase the dose.  
• Increase the dose of potassium-sparing diuretics when given insulin or other antidiabetic agents and decrease the dose of other antihypertensive agents.  
• You should ask the patient to drop bananas and dates, potassium-rich foods from their diet. Ask them to consume them only when their healthcare provider allows it.  
• For maximum effectiveness, administer amiloride with food and administer triamterene after meals. 
• Inform the patient that potassium-sparing diuretics may cause dizziness, headache, or vision disturbances. Advise the patient to avoid driving or performing activities requiring mental alertness or physical dexterity until his response to the diuretic is known. 

The Bottom Line

Potassium-sparing diuretics are essential agents, often combined with other diuretics, to prevent hypokalemia- a common complication with their therapy.  

That completes the nursing processes of potassium-sparing diuretics.  

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